Recruitment strategies, design, and participant characteristics in a trial of weight-loss and metformin in breast cancer survivors

Abstract

Weight loss and metformin are hypothesized to improve breast cancer outcomes; however the joint impacts of these treatments have not been investigated. Reach for Health is a randomized trial using a 2×2 factorial design to investigate the effects of weight loss and metformin on biomarkers associated with breast cancer prognosis among overweight/obese postmenopausal breast cancer survivors. This paper describes the trial recruitment strategies, design, and baseline sample characteristics. Participants were randomized in equal numbers to (1) placebo, (2) metformin, (3) weight loss intervention and placebo, or (4) weight-loss intervention and metformin. The lifestyle intervention was a personalized, telephone-based program targeting a 7% weight-loss in the intervention arm. The metformin dose was 1500 mg/day. The duration of the intervention was 6 months. Main outcomes were biomarkers representing 3 metabolic systems putatively related to breast cancer mortality: glucoregulation, inflammation, and sex hormones. Between August 2011 and May 2015, we randomized 333 breast cancer survivors. Mass mailings from the California Cancer Registry were the most successful recruitment strategy with over 25,000 letters sent at a cost of $191 per randomized participant. At baseline, higher levels of obesity were significantly associated with worse sleep disturbance and impairment scores, lower levels of physical activity and higher levels of sedentary behavior, hypertension, hypercholesterolemia, and lower quality of life (p<0.05 for all). These results illustrate the health burden of obesity. Results of this trial will provide mechanistic data on biological pathways and circulating biomarkers associated with lifestyle and pharmacologic interventions to improve breast cancer prognosis.

Objectively measured sedentary behavior and quality of life among survivors of early stage breast cancer

“…The TREC center was a program project examining the role of insulin resistance and inflammation in breast cancer risk [27]. Ninety-six overweight and obese women (BMI ≥ 25 kg/m 2 ) were recruited for the Reach for Health Study , a randomized trial examining the impact of metformin and weight-loss interventions on breast cancer mortality [28]. The baseline data used for this analysis were obtained prior to randomization into the intervention.…”

The effects of weight loss and metformin on cognition among breast cancer survivors: Evidence from the Reach for Health study

“…Measurements were collected during in‐person clinic visits conducted at baseline and 6‐month follow‐up. Details of the study design, recruitment, and interventions are described elsewhere . All participants provided signed informed consent, and the study was approved by the Human Research Protections Program at UC San Diego (IRB#101977).…”

“…In the current study, we investigate the impact of a 6‐month duration weight loss and metformin use on cognitive function among breast cancer survivors. Specifically, we test the impact of weight loss and metformin on changes in cognitive functioning in a sample of 333 overweight/obese early‐stage breast cancer survivors who were enrolled in the Reach for Health randomized trial . We also explore potential modifiers of the intervention effects.…”

Kernel Density Estimation as a Measure of Environmental Exposure Related to Insulin Resistance in Breast Cancer Survivors

“…The study used a 2 × 2 factorial design to assess how weight loss, metformin, or both influenced biomarkers associated with increased breast cancer mortality. The full study protocol is published in Patterson et al [41]. The RfH study obtained UCSD IRB approval and all participants provided written consent.…”